1,1'-Carbonyldiimidazole → tert-Butyl (S)-3-(6-tert-butoxycarbonylaminopyridin-3-yl)-2-[3-((8S,11R)-8-isopropyl-10-oxo-6-oxa-1,9,14-triazabicyclo[11.2.1]hexadeca-13(16),14-dien-11-yl)ureido]propionate

Participants

Reaction Steps

A solution of 56 mg (190 μmol) of (8S,11R)-11-amino-8-isopropyl-6-oxa-1,9,14-triazabicyclo[11.2.1]hexadeca-13(16),14-dien-10-one from step D in 5 ml of DMF was cooled to 0° C. and, while stirring, 32 mg (194 μmol) of 1,1′-carbonyldiimidazole were added. The mixture was stirred for 30 min, and then 64 mg (190 μmol) of tert-butyl (S)-2-amino-3-(6-tert-butoxycarbonylaminopyridin-3-yl)propionate were added, and the mixture was warmed to RT. After standing overnight, the same amount of 1,1′-carbonyldiimidazole was again added, and the mixture was stirred for a further 24 h. It was then concentrated and purified by preparative HPLC. 27 mg of the desired compound were obtained.

Provenance & Evidence